The Neuropathology Core is an essential part of the ADCC. The clinical syndromes generated by Alzheimer's disease (AD) and other neurodegenerative disorders associated with aging are not, of themselves, pathognomonic diagnostic phenomena. Neuropathological examination of the post-mortem brain is therefore the only means by which a definite diagnosis can be attained. A second major role of the Neuropathology Core is to provide neuropathologically characterized brain tissue to basic scientists, both within the ADCC and outside it, enabling them to discover the underlying molecular mechanisms of disease and design appropriate therapeutic interventions. A detailed understanding of the genetic and molecular processes of disease pathogenesis, obtained by comparative study of diseased and non-diseased brain tissue, remains the major approach to finding such interventions. A third important goal of the Neuropathology Core is to help develop a collaborative synergy that will enhance the research productivity of the entire Center. Our Specific Aims are as follows: 1) To provide precise neuropathologic diagnoses of patients who have been clinically studied. 2)To provide basic scientists with neuropathologically characterized brain tissue suitable for the elucidation of the molecular mechanisms of AD and related disorders. 3) To share neuropathological skills, expertise and knowledge with all ADCC investigators, facilitating a collaborative synergy that will enhance the research productivity of all. 4) To optimize usage of collected neuropathologic data within the ADCC and the scientific community at large. 5) To assist researchers in the study of the earliest stages of Alzheimer's disease, with the goal of identifying therapeutic strategies that will prevent the disease or slow its progress.